The present invention relates to a turbocharger lubricating oil sealing apparatus, and more particularly to an oil sealing apparatus which can be easily assembled.
In general, as shown in FIG. 1, a turbine wheel 2 is directly connected by a driving shaft 3 to a compressor wheel 4 within a turbocharger 1. When the turbine wheel 2 rotates with a pressure of an exhaust gas discharged from a combustion chamber 5, the rotation of the turbine wheel 2 is transmitted by the driving shaft 3 to the compressor wheel 4, thereby resulting in the rotation of the compressor wheel 4. This supplies a supercharged air into the combustion chamber 5.
In general, it takes a relatively length time to assemble a turbocharger. Hence, it has been requested to shorten the time necessary to assemble a turbocharger. The reason why it takes a relatively length time to assemble a turbocharger, a turbocharger includes a lubricating oil sealing apparatus therein. The structure of such an oil sealing apparatus is explained hereunder.
In the turbocharger 1, as shown in FIG. 9, the driving shaft 3 is lubricated with an oil introduced from an opening 6. After the lubricating oil lubricates the driving shaft 3 and so forth, the oil returns from an outlet opening 7 to a crank case (not shown in drawings) of an engine 8 shown in FIG. 1. However, a part of the oil happens to be suctioned by a vacuum into an intake passage 9 shown in FIG. 1, thereby resulting in the composition within the combustion chamber 5 of the engine 8. Such a vacuum is generated by a venturi effect occurred when an air flows through a restricted passage 12 defined between a compressor housing 10 and a center housing 11, shown in FIG. 9. Further, when a throttle valve 13 (shown in FIG. 1) rapidly opens, a vacuum occurs in the intake passage 9 according to the time delay responding to the compressor wheel 4. Such a consumption of the lubricating oil in the combustion chamber 5 is not preferable from the standpoint that the consumption of the lubricating oil causes an unusual combustion within the engine 8, the occurrence of a white smoke, and a decrease in a lubricating oil.
To obviate the foregoing drawbacks, a conventional turbocharger 1 includes a lubricating oil sealing apparatus 17 as shown in FIG. 9. This lubricating oil sealing apparatus 17 comprises a sealing collar 14, a retainer 15, and a deflector 16. The sealing collar 14 is fitted with some amount of pressure into the driving shaft 3. The retainer 15 is mounted on the center housing 11. The deflector 16 is mounted between the retainer 15 and a thrust bearing 19. The sealing collar 14 includes a sealing ring 27 thereon. The sealing collar 14 has a radial projection 18 which is a form of a disc plate. The projection 18 extends in a parallel relationship with the retainer 15 with a small clearance t.sub.1. Further, the projection 18 extends in a parallel relationship with the deflector 16 with a small clearance t.sub.2. Thus, the combination of the retainer 15, the projection 18 and the deflector 16 constitutes a structure which performs a labyrinth effect. The lubricating oil sealing apparatus 17 prevents the oil from being suctioned into the intake passage 9 by the effect of a labyrinth mechanism and further by the use of the sealing ring 27.
When the lubricating oil sealing apparatus 17 is assembled into the turbocharger 1, parts of the apparatus 17 are assembled by the following order.
Firstly, as shown in FIG. 11, the thrust bearing 19 is mounted on the driving shaft 3 in the condition shown in FIG. 10. Next, as shown in FIG. 12, a thrust collar 20 is fitted with some amount of pressure into the driving shaft 3. Next, as shown in FIG. 13, the deflector 16 is attached to the side wall of the thrust bearing 19. The sealing collar 14 is fitted with some amount of pressure on the driving shaft 3, as shown in FIG. 14. Further, as shown in FIG. 15, the retainer 15 is mounted on the outer peripheral portion of the sealing collar 14, and the deflector 16 is held between the retainer 15 and the thrust bearing 19. Next, as shown in FIG. 16, a stop ring 24 fastens the retainer 15 to the center housing 11. Thus, according to a prior lubricating oil sealing apparatus 17, it is troublesome to assemble the lubricating oil sealing apparatus 17 into a turbocharger. Hence, it takes a length time to assemble a turbocharger.